Racing will continue Friday at the northern California track where a jockey fell off his horse and later died. Jorge Herrera, 33, died Thursday at Eden Trauma Center in Castro Valley from a head injury. He was racing in his second event of the day at the track in Pleasanton when he was thrown from his horse, Morito, which appeared to clip the heels of another horse and stumble. Herrera lurched forward and went over Morito's head as the horse righted itself and continued. "He was stepped on by either his horse or…